1. Field of the Invention
This invention relates to a turf gauge. More particularly, this invention relates to a turf gauge for measuring the hardness of golf greens. As is known, golf courses are generally maintained so that fairways, roughs and greens meet certain standards. However, difficulties frequently arise in attempting maintain the eighteen green of any given golf course, particularly the hardness of a green, so that each has similar surface characteristics. Depending upon the degree of watering, wind conditions, exposure to the elements and the like, hardness may easily vary. The maintenance of such greens is particularly acute for tournament play conditions. For example, a great degree of care is usually taken that the greens have the same hardness so that a ball impacting on any one green will perform in the same manner for all greens.
2. Description of Prior Related Art
In the past, various types of penetrometers and hardness measuring device have been known. For example, U.S. Pat. Ser. No. 4,061,021 describes a recording penetrometer which provides a depth-penetration resistance graph as the penetrometer is forced into the ground. To this end, the penetrometer includes a probe for penetrating the ground as well as a second probe which terminates in a ground engaging foot portion at one end while the upper end cooperates with a scriber apparatus for scribing on pressure sensitive paper mounted on a drum.
U.S. Pat. Ser. No. 3,214,966 describes an instrument for indicating the "going", that is, the degree of hardness of race courses and the like. This instrument, however, relies upon a weight which is dropped onto a spring and a scale calibrated to measure the rebound of the weight as a measure of the "going". Reference is also made to penetrometers having a protection which is caused to penetrate a ground surface in response to a predetermined application of force with the depth of penetration being used to give an indication of the hardness of the ground or "going".
U.S. Pat. Ser. No. 2,130,751 describes an apparatus for determining the resistance of the ground and is similar to that described in U.S. Pat. Ser. No. 3,214,966.
U.S. Pat. Ser. No. 2,117,985 describes a soil plasticity testing apparatus for measuring resistance to penetration by water. In this case, the apparatus includes a needle which is penetrated into the earth at a selected rate of speed with the resistance encountered measured by a spring responsive ring.
U.S. Pat. Ser. No. 2,421,449 describes a hardness measuring instrument for materials such as soft rubber. In this case, a pin is mounted by two springs in a floating manner to abut against a plunger which is movable with the pin and which is held in place by a spring biased plunger in order to give a measure of the movement of the pin.
U.S. Pat. Ser. No. 3,498,120 describes a fabric strength measuring device which includes a handle in which a blade is placed against a fabric to be tested and is forced into a handle against a spring until the end of the blade is even with the end of the handle. The force requirement for that amount of displacement is then a measure of the hardness of the material.
U.S. Pat. Ser. No. 1,637,421 describes a pressure indicator which records the amount of pressure necessary to cause a person being treated to experience sensitiveness to any pain produced by reasons of the pressure.
In general, all of the devices described in the above-noted patents are rather cumbersome to use.